Evidence that niche specialization explains species–energy relationships in lake fish communities

Abstract

Summary1. Interspecific niche differences have long been identified as a major explanation for the occurrence of species-rich communities. However, much fieldwork studying variation in local species richness has focused upon physical habitat attributes or regional factors, such as the size of the regional species pool. 2. We applied indices of functional diversity and niche overlap to data on the species niche to examine the importance of interspecific niche differentiation for species richness in French lake fish communities. We combined this information with environmental data to test generalizations of the physiological tolerance and niche specialization hypotheses for species-energy relationships. 3. We found evidence for a largely non-saturating relationship (relative to random expectation) between species richness and functional evenness (evenness of spacing between species in niche space), while functional richness (volume of niche space occupied) peaked at moderate levels of species richness and niche overlap showed an initial decrease followed by saturation. This suggests that increased niche specialization may have allowed species to coexist in the most species-rich communities. 4. We tested for evidence that increased temperature, local habitat area, local habitat diversity and immigration affected species richness via increased niche specialization. Temperature explained by far the largest amount of variation in species richness, functional diversity and niche overlap. These results, combined with the largely non-saturating species richness-functional evenness relationship, suggest that increased temperature may have permitted increased species richness by allowing increased niche specialization. 5. These results emphasize the importance of niche differences for species coexistence in speciesrich communities, and indicate that the conservation of functional diversity may be vital for the maintenance of species diversity in biological communities. Our approach may be applied readily to many types of community, and at any scale, thus providing a flexible means of testing niche-based hypotheses for species richness gradients.

Building relevant ecological indicators with basic data: Species and community specialization indices derived from atlas data

“…2a), a pattern already documented for the regional flora of the French Alps (Boulangeat et al, 2012). At fine scales, greater niche partitioning is also expected when species richness (and possibly competition) increases (Mason et al, 2008). Here, we also found that specialist species tend to occur in richer assemblages (Fig.…”

Size diversity and species diversity relationships in fish assemblages of Western Palearctic lakes

“…A1), maybe reflecting that biogeographical differences and ecological processes (e.g. higher interspecific competition) at local or evolutionary scales lead to increased niche specialisation towards low latitudes, as has been found in several previous studies (Griffiths 2006, Reyjol et al 2007, Mason et al 2008, Tedesco et al 2012, Schleuter et al 2012, Cirtwill et al 2015.…”

Large-scale seaweed cultivation diverges water and sediment microbial communities in the coast of Nan'ao Island, South China Sea

“…Species-energy theories predict that low concentrations of oxygen, nutrients and solar energy could restrict primary production along the water column, which could lead to declines in species richness (Mason et al, 2008;Wright, 1983). Since many microbes in the ocean require oxygen for survival and growth, especially in important redox processes necessary for basic metabolism, DO in the water column is crucial to microbial communities in coastal ecosystems.…”